Refer to Stateless App Cookbook#Kernel.The intents on EVM chains are EIP191 signed signatures.To construct the message and validate the signed EVM intent, there are two steps:
Perform getDataHashByUser() call on any Stateless app to retrieve data hash.
Sign data hash
For signing, we will be abiding by the [EIP-191] standard(https://eips.ethereum.org/EIPS/eip-191). This is supported by popular libraries such as ethers and wallets.